AT16601U1 - Composite panel with lightweight concrete - Google Patents

Abstract

Composite panel (1) for laying as a floor covering or paving in an unbound construction, in particular outdoors, the composite panel (1) being a tile or facing concrete layer (130) which forms the walkable or passable top side of the composite panel (1) and an associated one Concrete layer (150) comprises, wherein the concrete layer (150) is formed from concrete with a dry bulk density ≤ 2300 kg / m3.

Description

The invention relates to a composite panel. Methods of making them are also disclosed. The composite panel may be a tile, such as e.g. B. a ceramic plate, and a bonded or bonded concrete plate. In embodiments, the composite panel can comprise a facing concrete layer forming the upper side and an associated rear concrete layer forming the lower side. The composite panel is primarily intended for, but not limited to, use as an outdoor floor panel, for example in sidewalk or road construction, in gardening and landscaping or for terrace construction.

Similar composite panels are known for example from EP 3 216 776 A1 and EP 3 216 774 A1. It describes a composite panel consisting of a tile glued to a concrete panel. The concrete slab has an open structure so that water can flow through this structure. To improve the strength of the adhesive connection, the cited documents suggest that the plates be connected by means of an elastic adhesive in order to obtain an adhesive connection that is as tension-free as possible. As an adhesive, a particularly foamed polymer adhesive is proposed, such as. B. polyurethane.

For the production of the composite slab, the above-mentioned documents suggest either gluing a hardened concrete slab onto the tile or inserting the tile into a mold and pouring flowable concrete onto the adhesive surface of the tile. The flowable concrete applied to the tile can optionally be compacted with a pressure of at least 2 bar and a maximum of 8 bar, for example in combination with a shaking movement, whereby it should be noted that the open structure of the concrete is maintained.

If the tile is glued to a hardened concrete slab, the process steps for producing and curing the concrete slab and then the process steps for joining the concrete slab with the tile are to be carried out first. This results in a relatively large number of process steps or a long process time for the production of the composite panel. When the tile is placed in a mold and the flowable concrete is applied to the tile, this requires the concrete to at least partially cure in the mold. This requires a relatively large number of forms, which is reflected in increased production costs or investment costs.

The open-pore structure of the concrete slab has the advantage that the water can run off, but also the disadvantage that water can penetrate into the concrete slab. Especially in winter, when short dew periods occur, which are followed by frost periods, there is a risk that water will collect in the concrete slab, and frost damage can occur due to the free-flowing freezing water.

The US 2009/0049793 A1 describes a composite panel, which consists of a tile glued to a concrete slab, and their manufacturing process. The tile is glued to a not yet hardened concrete slab. This composite body, including the adhesive connection, is then cured.

The invention has for its object to provide a composite panel for laying as flooring, which is suitable to be used outdoors, which is robust, especially against temperature fluctuations, and easy to manufacture, preferably also by hand.

The object is achieved with the subject matter of claim 1. Advantageous further developments result from the dependent claims, the description and the figures.

The invention is based on a composite panel for laying as flooring or paving in an unbound construction, especially outdoors. The composite panel comprises a tile or a facing concrete layer, which forms the visible, walkable or drivable top side of the composite panel, and a concrete layer connected to it. For example, the tile can be glued to the concrete slab or concrete layer or a concrete slab blank

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AT 16 601 U1 2020-02-15 become or be an Austrian patent office. Alternatively, a back concrete layer (concrete core) can be joined with the facing concrete layer using the hermetic method. The composite panel can thus comprise a facing concrete layer and a rear concrete layer joined therewith. According to the invention, the (back) concrete layer is formed from concrete with a dry bulk density <2300 kg / m ³ , in particular from lightweight concrete.

For example, the concrete layer can be made of concrete with a dry bulk density of 1300 kg / m ³ to 2300 kg / m ³ , in particular from 1800 kg / m ³ to 2100 kg / m ³ . Alternatively, the concrete layer can be made of lightweight concrete with a dry bulk density of 800 kg / m ³ to 2000 kg / m ³ .

[0011] The concrete layer is preferably compact concrete or lightweight concrete with grain porosity. The structure-sealed concrete or lightweight concrete is characterized in that the cavities between the aggregate grains or bodies are filled with cement paste or closed-pore concrete. The aggregates, especially the aggregate grains, have an increased or high porosity (up to 85 vol.%), Whereby a weight-reduced concrete or lightweight concrete is achieved. The advantage of the sealed concrete or lightweight concrete is that water does not penetrate into the hardened concrete or lightweight concrete, making the (lightweight) concrete layer or the (lightweight) concrete slab less sensitive to frost. On the other hand, the structure-tight (light) concrete achieves a high strength of the concrete layer, which does not necessarily, i. H. only optionally requires the use of reinforcement. Due to the weight-reduced concrete or lightweight concrete, the mass of the composite slab decreases compared to the use of standard concrete for the concrete slab or the back concrete layer. This means that even large-format panels, for example in the format of 600x600 mm or 800x400 mm, can be laid by hand. Conventional large-format panels are to be installed mechanically if handled properly, since they are not suitable for manual laying due to their high mass, in accordance with the Load Handling Ordinance. Therefore, conventional composite panels intended for manual laying have significantly smaller formats.

The concrete of the concrete layer can have aggregates in the form of broken or washed granules from frost-proof rocks, glass, blast furnace slag, organic granules (plastics), foam lava, volcanic slate, expanded or foam glass (PORAVER®), expanded clay, gas concrete, foamed plastics or Plastic body, in particular thermosetting or thermoplastic plastics, such as Have polystyrene, polyurethane, etc. The grain sizes of these slammed bodies can vary as desired within certain limits. For example, the grain sizes can be 0/1 to 1/4 (mm) to 0/2 to 4/8 (mm). Gray cement / white cement according to DIN EN 197-1 or CEM I 42.5; CEM II BS 42.5 come into question. In principle, other cements are also possible.

For example, the following properties are achieved with the composite panel according to the invention or the composite panel can be or are adapted by the concrete layer designed according to the invention in order to have the following properties:

format Mass per composite panel Composite panel thickness 400x800 mm 22-26 kg, especially 23-25 kg 35-45 mm, especially 40-42 mm 600x600 mm 23-28 kg, especially 24-27 kg 35-45 mm, especially 40-42 mm

With the composite panel according to the invention, bending-tensile strengths of N> 5-— are also achieved. Furthermore, the frost-de-icing salt resistance according to EN 1339 is fulfilled.

As an alternative to the structure-sealed concrete or lightweight concrete with grain porosity, bulk-pored concrete or lightweight concrete with porous aggregates can be provided. Heap-pore concrete or lightweight concrete with porous aggregates is characterized by the fact that the aggregate is selected in such a way that as much hollow space as possible is created between the grains. The award basket

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AT 16 601 U1 2020-02-15 Austrian patent office ner are only covered by the cement and cemented together at points. This results in even lower masses for the composite panel. However, high-pore concrete or lightweight concrete is not closed-pore, so that water can penetrate into the back concrete layer or the concrete slab. This makes the composite panel more susceptible to frost. However, it can be used advantageously in areas where frost is not to be expected.

The composite panel has a solid, plate-shaped tile or a facing concrete layer, which forms a visible side or surface or the upper surface of the composite panel, and a concrete slab or layer, which in the installed state is not visible side or surface or the forms the lower surface of the composite panel. The lower surface is when laying the composite panel on a granular base or bed, such as. B. a grit, gravel or sand bed, positioned and placed on it. The upper surface of the composite panel, in particular the facing concrete layer or the tile, is then accessible or visible. The surface forming the upper side of the tile (upper surface of the tile or the facing concrete layer) is bordered or delimited by peripheral surfaces, in the case of a rectangular tile or facing concrete layer by its four peripheral surfaces. The surface forming the underside of the concrete slab or layer (lower surface of the concrete slab) is bordered or delimited by circumferential surfaces, in the case of a rectangular concrete slab or layer by four circumferential surfaces.

The invention also relates to a floor covering that has a substructure with at least one bed of grit, sand or granules, and several composite panels laid on the bed in a bond, joints being formed between the composite panels and the composite panels being designed as described herein , In particular, the composite panels are intended for laying in unbound construction, i. that is, the composite panels, in particular with their lower surfaces, lie loosely on the bed and are not glued to a substrate or the bed.

The tile or layer of facing concrete can have a smaller thickness than the concrete slab or layer. The tile can e.g. B. a ceramic tile, cement tile, stone or natural tile or earthenware tile.

A possible method for producing a composite panel, in particular in the hermetic method, comprises introducing a layer of facing concrete (facing concrete layer) into a mold, in particular a hermetic mold, such that the facing concrete preferably completely covers a bottom of the mold. The bottom can be surrounded by side walls, in particular four side walls, which are perpendicular to one another and can form a square or rectangle in cross section. The side walls border the bottom of the mold. In particular, the facing concrete can be applied to the bottom of the form so that it completely covers it.

On the layer of facing concrete, the layer of concrete or lightweight concrete (lightweight concrete layer), which has a dry consistency with respect to the layer of facing concrete, is introduced.

[0021] In particular, the layer is distributed on the layer of facing concrete so that it completely covers the layer of facing concrete.

The facing concrete layer and the concrete layer applied thereon with a vertical or normal, on the layers, i.e. H. in the direction of the thickness of the layers, acting press force. The shape, in particular the hermetic shape, is sealed with regard to water leakage from the shape during pressing. Pressing forces water from the facing concrete layer into the concrete layer on top of it. This connects the concrete layers. The facing concrete layer and the concrete layer applied thereon are preferably compacted by the pressing to form a composite panel blank which is so stable that it can be removed from the mold in the uncured state and fed to further processing. For example, the composite sheet blank is removed from the mold and then cured, for example in the manner described in the present application. Because the uncured composite panel blank is so strong

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AT 16 601 U1 2020-02-15 Austrian patent office holds that that it can be removed from the mold, the number of molds is reduced enormously compared to designs in which the composite panel hardens in the mold.

The method for producing a composite slab, which has a tile and an associated, in particular glued concrete slab, includes, for example, the introduction of said concrete, in particular with a dry bulk density of <2300 kg / m ³ or lightweight concrete, for the concrete slab in a mold , in particular mold, wherein the concrete is compacted in the mold by pressing to form a concrete slab blank. Thereafter, in particular to form an adhesive layer, the adhesive is applied either to the concrete slab blank or to the tile or to both the concrete slab blank and the tile, in particular to the lower surface of the tile and / or the upper surface of the concrete slab blank. Optionally, an adhesion promoter, primer or a primer can be applied to the lower surface of the tile and / or the upper surface of the concrete slab blank before applying the adhesive or before joining.

The concrete slab and the tile are put together after the application of the adhesive, in particular the adhesive layer, in particular by means of the adhesive located in between, which is in front of at least one of the concrete slab and tile, in particular on the lower surface of the tile and / or the upper Surface of the concrete slab was applied. After joining, the adhesive (or the adhesive layer) and the concrete slab are hardened. The hardened concrete slab blank is then the concrete slab. That is, the concrete slab and the concrete slab blank essentially differ only in that the concrete slab blank has not yet hardened while the concrete slab is hardened.

Due to the joint hardening of the adhesive and the blank slab, mechanical stresses between the adhesive and the blank slab decrease in comparison to a sticking of the tile with a hardened concrete slab. This improves the resistance to temperature differences, making the composite panel particularly suitable for laying outdoors. In addition, by joining the tile with the concrete slab blank or with the concrete slab before it has hardened, the process time for producing the composite slab is shortened. If the tile is glued to a hardened concrete slab, the concrete slab must first be hardened, after which the tile is glued to the concrete slab. The adhesive connection in turn needs time to harden again. Therefore, the process time or time for the production of the composite slab can be considerably reduced by the joint hardening of the adhesive and the concrete slab blank. The fact that the tile does not have to be inserted into the mold as in other methods in order to glue the flowable concrete to the tile, protects the visible surface of the tile.

[0026] For example, the concrete in the mold can be compacted into a concrete slab blank by pressing with a pressure of at least N N 2.4 or more or at least 12. These pressures create a structure-tight structure of the lightweight concrete in the composite slab blank or the concrete slab blank or the later concrete slab. The structure-dense structure means that during alternating frost and thaw periods in winter, little or no water is absorbed into the concrete slab or back-concrete layer, which significantly reduces the risk of frost damage. In addition, these minimum pressures ensure that the concrete is also in an uncured state, i.e. H. as a composite or concrete slab blank, holds together so tightly that it can be removed from the (pressed) shape while maintaining its shape, in particular the geometric shape obtained from the (pressed) shape. In other words, the composite or concrete slab blank maintains its geometric shape given by the (press) shape during demolding and also afterwards, as a result of which the concrete slab blank can be handled as a solid. As a result, the concrete slab blank z. B. can be picked up by a gripper and fed to further work steps without it having to remain in the mold. This ensures that relatively few forms compared to processes in which the concrete hardens in the form

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AT 16 601 U1 2020-02-15 Austrian patent office, which can reduce the investment costs for the procurement of the molds.

The facing concrete layer and the back concrete layer can by pressing with an N N

Pressure of a maximum of 50 - or a maximum of 32 - to a concrete slab blank or Vermm ² .. mm ² slab blank are compressed. In principle, pressures exceeding these maximum pressures are possible, but no longer have any noteworthy positive effects with regard to the structure-sealed structure and the cohesion of the concrete slab blank or the lightweight concrete layer.

The compaction by pressing can be carried out, for example, by means of a pressure ram which acts on the concrete introduced into the mold, which is open at the top in relation to the direction of gravity. For example, the concrete can be pressed towards the composite slab or concrete slab blank in the direction that corresponds to the direction of the thickness of the composite slab or concrete slab or concrete slab blank.

The shape in which the concrete is introduced can have a bottom and side walls, the side walls defining the geometric peripheral shape or the peripheral surfaces of the concrete slab or the concrete slab blank. For example, the concrete slab or the concrete slab can be rectangular with respect to the circumference or have another desired shape. Accordingly, the concrete slab or the concrete slab blank can be rectangular in cross section perpendicular to the direction of the thickness of the concrete slab or just have another specific geometric shape. The rectangular shape also includes a square shape.

The internal dimensions of the shape in terms of length and width can correspond to the external dimensions of the concrete slab blank and / or the concrete slab and / or the tile, if applicable. For example, each of the circumferential surfaces of the tile can be flush with a circumferential surface of the concrete slab blank or the concrete slab. This ensures that the tile is congruent or congruent with the concrete slab. In other words, the concrete slab or the concrete slab blank can have the same external dimensions in terms of length and width as the tile.

Alternatively, the internal dimensions of the (press) shape can be larger in terms of length and width, in particular by up to 6 mm, in particular by up to 4 mm or up to 2 mm, than the external dimensions of the tile in relation on length and width. For example, each of the peripheral surfaces of the concrete slab blank or the concrete slab can be arranged offset up to 3 mm, in particular by up to 2 mm or by up to 1 mm from the peripheral surface of the tile assigned to it. The effect that can be achieved in this way is that the side edge of the finished composite slab closest to the floor, the composite slab generally being transported upright, is protected or protected from damage, since it is ensured that it is not the side edge of the tile but a peripheral surface of the concrete slab rests on the bottom of the transport unit.

Optionally, spacers can be or are attached to the peripheral surfaces of the concrete slab or the concrete slab blank, which are flush with or outwardly offset from the peripheral surfaces of the tile, which have the effect that the composite slab forms a defined joint with a composite slab attached next to it when the composite panels are laid on the laying bed. Such spacers are described for example in EP 3 112 331 A1. Accordingly, the side wall of the (press) mold can have recesses for the spacers.

Optionally, the concrete of the concrete layer mentioned additives in the form of hydrophobization, titanium oxide compounds, flow agents, compressors, retarders, accelerators and all additives that serve to optimize the concrete properties and processing can be mixed into the concrete.

The concrete of the concrete layer applied to the facing concrete layer or the concrete

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AT 16 601 U1 2020-02-15 Austrian patent office slab or the concrete slab can be made without reinforcement or with reinforcement such as B. structural steel mesh, steel fibers, glass, carbon and aramid fibers and fabrics formed therefrom.

[0035] For example, the blank of the concrete slab and the tile can be glued over the entire surface by means of the adhesive. For example, the adhesive can be applied to at least one of the entire surface of the concrete slab and tile, in particular with or without a profile, such as. B. a tooth profile.

A full-surface gluing reduces the risk of water penetrating between the tile and the concrete slab. In addition, the full-surface gluing reduces the risk of damage to the tile when the surface is loaded when the composite panel is installed.

As an adhesive, tile cement based cement such. B. cement adhesive or flexible adhesive. In particular, the adhesive can be a mineral adhesive, such as, for example, a polymer-modified mineral adhesive or adhesive mortar.

[0038] In particular, the adhesive may comprise mineral binder or as a binder at least for the most part mineral binder. The cement-based adhesive or an adhesive that includes mineral binder as a binder or mineral binder for the most part can be used to create a permanent, high-quality connection between the tile and the concrete slab that can withstand the weather conditions outdoors.

[0039] A polymer-modified mineral adhesive or adhesive mortar can have the following compositions, for example:

Portland cement 25 to 55% lime 0 to 3% additives 0 to 10% sand, dense 0 to 0.5 mm 20 to 60% dispersion powder, methyl cellulose, stabilizer, hardening accelerator Air-entraining agents and fibers 0 to 20%. By means of the above-mentioned methods, a composite panel for laying as a floor covering or paving, in particular outdoors, can be produced, the composite panel having a facing concrete layer and an associated backing concrete layer (concrete core) or a tile and a with it glued concrete slab.

In advantageous developments, the peripheral surfaces of the tile can be flush with the peripheral surfaces of the concrete slab, whereby the tile and the concrete slab are congruent or congruent. In alternative advantageous developments, each of the circumferential surfaces of the concrete slab blank or the concrete slab can be arranged offset to the outside by up to 3 mm, in particular by up to 2 mm or by up to 1 mm from the circumferential surface assigned to it. As mentioned above, this results in advantages when transport is standing, for example, but also when handling the composite panel in such a way that the edges of the tile are protected and the risk of damage is reduced.

In particular, the tile was joined to the concrete slab by gluing, in particular by gluing over the entire surface, when the concrete slab was already pressed, in particular was already pressed to a concrete slab blank and was uncured. This results in the advantages mentioned above, in particular with regard to better resistance to temperature fluctuations due to reduced mechanical stresses between the adhesive and the concrete slab during the manufacturing process and an inexpensive possibility of producing the composite slab.

At the hardened concrete slab blank or the concrete slab can by Untersu

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AT 16 601 U1 2020-02-15 Austrian patent office, it was found that the tile was joined to the concrete slab by gluing when the concrete slab was pressed and uncured.

Due to the, in particular full-surface, bonding of the concrete slab and the tile by means of a cement-based adhesive or a mineral adhesive, such as, for example, a polymer-modified mineral adhesive or adhesive mortar or an adhesive which largely comprises mineral binders or as a binder, a high-quality connection can be made between the concrete slab and the tile, which also meets the requirements that are imposed when used outdoors.

The term thickness (or height) used herein is understood as the distance between an upper surface and a lower surface. Length and width are to be understood as orthogonal to each other and to the thickness.

The invention has been described with reference to several embodiments and examples. A composite panel is described below with reference to figures. The features disclosed thereby form the subject of the invention individually and advantageously in any combination of features. Show it:

FIG. 1 [0053] FIG. 2 [0054] FIG. 3 a composite panel in an unbound construction on a laying bed, a perspective view of FIG. 1 and a perspective view of a further embodiment of a composite panel.

In Figures 1 to 3 an example laid on a bed 2 composite panel 1 is shown.

The composite panel 1 from Figures 1 and 2 has a tile 30 which is glued to a concrete panel 50 by means of an adhesive layer 40. The upper surface 31 of the tile 30 forms the visible surface of the installed composite panel 1. The lower surface 52 of the concrete panel 50 is the surface of the composite panel 1 resting on the bed 2. The lower surface 32 of the tile 30 and the upper surface 51 of the concrete panel 50 are connected by means of the adhesive layer 40 and wetted with the adhesive. In the example shown, the circumferential surfaces 53 of the concrete slab 50 that surround or delimit the lower surface 52 and / or the upper surface 51 are flush with the circumferential surfaces 33 of the tile 30 that enclose the upper surface 31 and / or the lower surface 32 is thus congruent or congruent to the concrete slab 50.

In an alternative, not shown with reference to figures, the external dimensions of the concrete slab 50 with respect to length and width, measured in each case between opposite circumferential surfaces 53, which border or delimit the upper surface 51 and / or the lower surface 52, can be larger , in particular by up to 6 mm, in particular by up to 4 mm or up to 2 mm, larger than the external dimension of the tile 30 in terms of length and width, in each case measured between opposite circumferential surfaces 53, which are the upper surface 31 and / or border or delimit the lower surface 32. For example, each of the circumferential surfaces 53 of the concrete plate 50 enclosing or delimiting the upper surface 51 and / or the lower surface 52 can be the upper surface by up to 3 mm, in particular by up to 2 mm or by up to 1 mm 31 and / or the peripheral surface 33 of the tile 30 enclosing or delimiting the lower surface 32 can be arranged offset to the outside.

The tile 30 and the concrete slab 50 were glued by means of the adhesive layer 40, which was arranged on at least one of the lower surface 32 of the tile 30 and the upper surface 51 of the concrete slab 50, by pressing the tile 30 and the concrete slab 50 together in one by pressing but uncured state of the concrete slab 50 (concrete slab blank). This results in a high-quality and inexpensive to produce composite panel.

The composite panel from Figure 3 has a facing concrete layer 130, which with

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AT 16 601 U1 2020-02-15 Austrian patent office using the hermetic method with a back concrete layer 150 is joined or connected. The upper surface 131 of the facing concrete layer forms the visible surface of the installed composite slab 1. The lower surface 152 of the rear concrete layer 150 is the surface of the composite slab 1 lying on the bed 2. The peripheral surfaces 153 of the rear concrete layer 150 bordering or delimiting the lower surface 152 are shown in FIG In the example shown, it is flush with the peripheral surfaces 133 of the facing concrete layer 130 that enclose or delimit the upper surface 131. The facing concrete layer 130 is thus arranged congruently or congruently with the rear concrete layer 150. The facing concrete layer 130 and the backing concrete layer 150 were joined by means of a method in which the facing concrete layer 130 is first introduced into a mold in such a way that the facing concrete 130 preferably completely and particularly preferably covers a bottom of the mold with a uniform thickness. Then the back concrete layer 150 is placed in the mold on the facing concrete layer 130. The back concrete layer 150 preferably covers the facing concrete layer 130 completely and / or with a uniform thickness. The back concrete layer 150 has a drier consistency with respect to the facing concrete layer 130. In particular, the facing concrete layer is more flowable than the backing concrete layer. The facing concrete layer 130 and the backing concrete layer 150 are pressed in the mold with a pressing force acting perpendicularly or normally on the layers, as a result of which a proportion of water is pressed or rises from the facing concrete layer 130 into the lightweight concrete layer 150. As a result, the facing concrete layer 130 and the rear concrete layer 150 bond particularly well. Ideally, the consistencies of the facing concrete layer 130 and the backing concrete layer 150 as well as the compression pressure are selected such that the pressing forms a composite plate blank comprising the facing concrete layer 130 and the backing concrete layer 150, which can be removed from the mold, even if the layers 130, 150 are not are cured. By curing the composite sheet blank, d. H. the facing concrete and the rear concrete layer 130, 150, for example in a climatic chamber, the composite panel 1 is formed.

According to the invention, the concrete slab or the concrete slab 50 from FIGS. 1 and 2 or the back concrete layer 150 from FIG. 3 are made from weight-reduced concrete with a dry bulk density <2300 kg / m ³ or from lightweight concrete (dry bulk density between 800 kg / m ³ and 2000 kg / m ³ ). In the examples shown in FIGS. 1 to 3, the (light) concrete is a structure-sealed (light) concrete with grain porosity. The (light) concrete contains aggregates 100, for example in the form of grains of certain grain sizes, which have an increased porosity. The structure between the aggregates 100, in which the aggregates 100 are embedded, is preferably closed-pore. This prevents or makes it difficult for water to penetrate into the concrete slab 50 or the rear concrete layer 150, as a result of which the composite slab 1 is particularly frost-proof. Nevertheless, the composite panel 1 has a low mass due to the additions 100, as a result of which the composite panel 1 can also be laid by hand in large-format versions.

Optionally, one or more spacers (not shown) protrude from at least one or from each of the circumferential surfaces 53, 153 of the concrete slab 50 or the back-concrete layer 150, which are provided to provide a defined distance with a defined joint to an adjacent composite slab enable.

The lower surface of the composite panel 1 52, 152 lies loosely on the laying bed 2. The bed 2 can consist of grit, sand or another granular material, as is customary in paving.

Claims (13)

1. composite panel (1) for laying as flooring or paving in unbound construction, especially outdoors, the composite panel (1) a tile (30) or facing concrete layer (130), which forms the top of the composite panel (1), and a connected concrete layer (50, 150), characterized in that the concrete layer (50, 150) is made of concrete with a dry bulk density <2300 kg / m ³ . 2. Composite panel (1) according to claim 1, wherein the concrete layer (50, 150) made of concrete with a dry bulk density of 1300 kg / m ³ to 2300 kg / m ³ , in particular from 1800 kg / m ³ to 2100 kg / m ³ or the concrete layer (50, 150) is made of lightweight concrete with a dry bulk density of 800 kg / m ³ to 2000 kg / m ³ . 3. Composite panel (1) according to claim 1 or 2, wherein the concrete of the concrete layer (50, 150) aggregates (100) comprises at least one of the following: broken or washed granules made of frost-proof stone, glass, blast furnace slag, organic granules (plastic) , Foam lava, volcanic slate, gas concrete, expanded or foam glass, expanded clay, foamed plastic or plastic body, in particular thermosetting or thermoplastic plastic, such as Polystyrene, polyurethane. 4. Composite panel (1) according to one of claims 1 to 3, wherein the concrete layer (50, 150) aggregates (100) with grain sizes from 0/1 to 1/4 (mm) to 0/2 to 4/8 (mm) , especially from 0/2 to 1/4 (mm). 5. Composite panel according to one of claims 1 to 4, wherein the concrete layer (50, 150) gray cement / white cement according to DIN EN 197-1 or CEM I 42.5; Contains CEM II BS 42.5. 6. Composite panel (1) according to one of claims 1 to 5, wherein the concrete layer (50, 150) is designed without reinforcement or reinforced with reinforcement, in particular structural steel mesh, steel fibers, glass, carbon or aramid fibers or a fabric formed therefrom , 7. composite panel (1) according to any one of claims 1 to 6, wherein the tile (30) with the concrete plate (50) is joined by gluing. 8. Composite panel (1) according to one of claims 1 to 6, wherein the facing concrete layer (130) and the associated concrete layer (150) are joined by means of the hermetic method. 9. Composite panel (1) according to one of claims 1 to 8, wherein the concrete layer (50, 150) is structural concrete, in particular lightweight concrete, with grain porosity. 10. Composite panel (1) according to one of claims 1 to 8, wherein the concrete layer (50, 150) is aggregate-pored concrete, in particular lightweight concrete, with porous aggregates. 11. Floor covering which has a substructure with at least one bed (2) made of grit, sand or granules, and several composite panels (1) laid in association on the bed (2) according to one of the preceding claims, wherein between the composite panels (1) Joints are formed. 12. Floor covering according to claim 11, characterized in that the underside of the composite panels (1), with which the respective composite panel (1) rests on the bed (2), connected by the facing concrete layer (130) or the tile (30) Concrete layer (50, 150) is formed. 13. Floor covering according to claim 11 or 12, characterized in that the composite panels (1) are laid in an unbound construction on the bed (2).